The invention relates to a process for renovating pipes, which comprises the steps of removing internal deposits in the pipe by flowing abrasives and applying an inside coating of a viscous curing material.
Basically, it should be remarked at this point that the pipes to be renovated are already installed lines, which may carry gas, vapor, or liquid. Thus, the pipes may include, for example, feed and/or drain pipes for water or gas in residential, industrial, and municipal areas. This also includes residential and industrial sewer lines. All of these lines tend to form incrustations, which result primarily from calcareous deposits from the water, corrosion on the inside wall of the pipe, precipitates from the flow medium, products of reaction between the flow medium and entrained substances as well as the material of the pipe, etc., and from a combination of effects resulting therefrom. The foregoing phenomena lead to leaks or very considerable reductions of the inside cross sections of the pipes, whereby the transportation of the flow medium is disturbed, if not even prevented.
The presently claimed process for renovating pipes assists in avoiding a total replacement of the pipes, which turns out to be especially advantageous with respect to completely installed plumbing equipment. In this instance, the pipes are more or less freely accessible after removal of the fixtures, so as to permit application of the claimed cleaning and coating process. Essential is at any rate that a pipe be accessible at least at two open ends, so as to be able to carry out the individual steps of the process. The claimed process does not preclude an at least partial conventional repair of the pipes, so that it is also quite possible to replace complete pipe systems in part and to renovate same in part by the claimed process.
Processes of the aforesaid kind have been known from practice for quite some time. only as an example, reference is made in this context to EP 0 299 134. This European Patent discloses a process of this kind, in which the removal of internal deposits in the pipes and internal coating of the pipes occurs exclusively by means of compressed air. In other words, in the known process, compressed air is forced as a carrier medium through the pipe. When removing internal deposits, the transportation of the abrasive, which occurs exclusively by compressed air, leads to cloggages of the pipe, especially in the case of substantial internal deposits and, thus, requires quite considerable efforts to remove the cloggages. Flat parts that have been torn off by the compressed air are prone to accumulate just in the region of elbows or bends. Eventually, these accumulations will lead to a total blockage of the pipe.
Furthermore, the known method has the great disadvantage that while carrying out the process or during the application of compressed air, it is practically impossible to detect leaks. Consequently, there exists the risk that despite enormous leaks the inside wall is coated, which practically prevents a stopping of the leaks. In this respect, a large leak or hole in the pipe is virtually "improved" by the coating, and can no longer be effectively closed.